Circulating and cooling system for a liquid metal or metal alloy with mold element



NOV. 14, 1961 c o ETAL 3,008,271

' CIRCULATING AND COOLING SYSTEM FOR A LIQUID METAL 0R METAL ALLOY WITHMOLD ELEMENT Flled Jan 23, 1957 4 Sheets-Sheet 1 I INVENTORS \/0/7 A/56% BY Edi/ilf//M/A/fltb Nov. 14, 1961 CIRCULATING AND COOLING SYSTEM FORA LIQUID METAL 0R METAL ALLOY WITH MOLD ELEMENT Filed Jan. 25, 1957 J.E. COOK ETAL 4 Sheets-Sheet 2 /zz 2'5 x/ L Z INVENTORJ AMA/'6: (00% BY.ZJfia'A/MA/flfo Nov. 14, 1961 5, 300 ETAL CIRCULATING AND COQLINGSYSTEM FOR A LIQUID METAL 0R METAL ALLOY WITH MOLD ELEMENT 4Sheets-Sheet 3 Filed Jan. 23, 1957 IN VENTORJ x/ fi A/ 5 (004iuszyr-Alwfl/meo Ma 7e? Nov. 14, 1961 J. E. COOK ETAL CIRCULATING ANDCOOLING SYSTEM FOR A LIQUID METAL OR METAL ALLDY WITH MOLD ELEMENT FiledJan. 23, 1957 4 Sheets-Sheet 4 I I Z! I j r 1 44M i L 2.6

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Unite Our invention relates to equipment including means for circulatingan active liquid metal or metal alloy in a closed circuit. The liquidwhich serves as a coolant or heat extracter, is raised to a hightemperature while in contact with a workpiece such as a hot mold orother part at a high temperature. The liquid metal is then cooled bypassing it through a cooling medium or heat exchanger at another pointin its path of circulation.

The invention may be used with various forms of mechanisms and forvarious purposes. It is of utility when employed in connection with apress molding machine such as used for press molding glass articles andis herein illustrated and described as adapted for this particular use.Such illustration and description, however, are not to be taken aslimitations of the invention to the particular uses to which it may beput nor the mechanisms with which it may be employed, except as limitedby the appended claims.

In a machine for molding glass articles the molds are subjected to hightemperatures and some means for cooling and regulating the temperatureof the molds is essential. Ordinarily air cooling systems are used forthis purpose. Attempts to use water and liquids generally for suchcooling purposes are opened to various objections and particularilycannot be used at the high temperatures of the molds on account ofvolatilization or low boiling points. The use of a metal in liquid formas a heat extracting medium has important advantages, particularly whererapid extraction of heat is required, but the use of any metals whichremain in liquid form throughout the necessary range of temperatureshave been found to involve practical difliculties, largely due to thefact that any metals or metal alloys which have a sufliciently lowmelting temperature for such use are very active in the presence of airor oxygen in any form, particularly water or moisture, so that it isnecessary to prevent contact with air or moisture at all times.

In a machine such as above mentioned for press molding glass articles,the mold is commonly moved to and from a molding position, thusrequiring relative movement of the parts comprised in the circulatingsystem for the liquid metal. A primary object of the present inventionis to provide a construction in which an externally cooled seal isprovided between the circulating liquid metal and the atmospheer whichis kept out of contact with the liquid metal. This feature eliminatesmany problems encountered with ordinary type packings, flexible jointsand hoses which must be operated in direct contact with the liquidmetal.

The apparatus as herein illustrated for practicing the inventioncomprises tanks which may be mounted side by side, each of a capacity tocontain the entire volume of liquid metal in the system. Each tank isprovided with a well extending downwardly from the floor of the tank andopen to the liquid metal in the tank. Each tank is fitted with a packinggland sleeev extending upwardly therefrom in line with the well. Thevertically moving ram which carries the mold has connected thereto, twotube assemblies each comprising concentric inner and outer tubes with aninsulating space therebetween. These tube assemblies extend downwardinto the tank with the inner tube extended into the well 'below thetank. The

States Patent 3,008,271 Patented Nov. 14, 1961 packing gland sleevessurround the said concentric tubes, with suitable insulation between thetubes and the packing gland sleeves.

Other objects of our invention and various features of novelty willappear hereinafter in connection with the following detaileddescription.

Referring to the accompanying drawings:

FIG. 1 is an elevation, with parts broken away and with parts shown insection, of a press molding machine to which the invention is applied;

FIG. 2 is a sectional elevation of one of the tanks and the associatedtube assembly comprised in the liquid metal circulating system;

FIG. 3 is an elevation of the machine as viewedin a direction at rightangles to that of FIG. 1;

FIG. 4 is a plan view of the machine;

FIG. 5 is an elevation view, partly diagrammatic, showing a portion ofthe metal circulating system and heat exchangers;

FIG. 6 is a view similar to FIG. 2 on a comparatively large scale andalso showing the press plunger head and mold.

Referring to the drawings: The press plunger mechanism is supported on abase 10 on which is mounted a superstructure comprising upright framemembers 11 which support an upper frame structure 12. The press plungercomprises a hydraulic cylinder 13 and piston rod or plunger 14 which maybe vertically reciprocated in a manner well known to those skilled inthe art. Attached to the rod 14 at its upper end is a head 15 formedwith a cavity 16 which provides a cooling chamber in which the hollowmold 17 is supported. The mold is attached 'by bolts 18 to the head 15.The walls of the chamber 16 are spaced fromrthe mold walls to providefor the circulation of the cooling liquid in contact with the mold. Moldcharges or gobs of molten glass ll? are periodically dropped into themold.

The heat extracting liquid 9 7 (FIG. 6) used with the present inventionconsists preferably of a metal alloy, specifically a 22% sodium, 78%potassium alloy. Such an alloy has a low melting point such that it maybe used at room temperatures or within a practical range of temperaturesto which it is subjected. These may include temperatures from 700 to1500 F., these high temperatures being reached while in contact with thehot mold walls in which the molten glass is molded. The inventioncontemplates also the use of gallium and any other metal or metal alloywhich remains in liquid form throughout the range of temperatures towhich it is subjected when used for the purpose of the presentinvention.

The head 15 has connected thereto or formed integral therewithhorizontal arms 20 and 21 extending radially therefrom and carryingrespectively tube assemblies 22 and 23. These tube assemblies areattached to the arms 20, 21 by means of heads or disks 24 and bolts 25(FIG. 6). Attached to and depending from each head 24 are concentricvertical tubes including an inner tube 26 and outer tube 27 with anintervening space. The tubes 26 and 27 are sealed together at theirupper and lower ends, thereby providing a sealed chamber com-prising anannular space between the tubes. The purpose of this construction is toprovide a heat barrier between the inner tube, through which the liquidmetal flows, and the outer tube where a seal is made between the tubesand the outside air as presently described. The enclosed space betweenthe two tubes can be evacuated or insulated either with an inert solidmaterial or simply left as a dead air space, depending upon the amountof heat stoppage or insulation required. A pair of tanks 30 and 30 havea stationary mounting on the framework 12 and serve as reservoirs forthe liquid metal. These tanks are preferably made of stainless steelwhich is insert or resistant to the liquid metal. Each tank is formedwith a bottom opening 31 through which the inner tube 26 extendsdownward into a well 32. The tube 26 when lowered extends below the tankagreater distance than the length of stroke of the press plunger, sothat the lower end of the tube is always within the well and immersed inthe liq- The well is secured to the floor of the tank 30.

uid metal.

Surrounding the vertically reciprocating tubes 26, 27 is a packing glandsleeve 34 fixed to the frame 12. The upper half or upper portion of thesleeve 34 is of Suthcient internal diameter to provide a packing chamberbetween the sleeve and the tube 27. This chamber comprises an uppersection 35 and a lower section 36 separated by a chamber 37. An inertgas is introduced in this chamber at the same pressure as exists in theassociated tank unit. As shown the packing gland sleeve 34 is formedwith a bore 3-8'opening. into the chamber 37 and extendingdownwardly'therefrom through said sleeve and in communication with theinterior of the tank 30. As the circulating metal must be kept out ofcontact with the air and moisture, an inert gas such as nitrogen ismaintained within the tank at any desired pressure. This gas isintroduced through a pipe 40 and the level of the liquid in the tank ismaintained by varying the pressure applied through the pipe '40. It willbe apparent that the pressure within the chamber 37 is the same as thatwithin the tank. This balanced pressure above wardly through the packingand escaping. Pipes 35 and 35 permit the circulation of a coolingliquid, such as kerosene, through the packing material. An outer metalshell 41 attached to the head 24 surrounds and telescopes with thepacking gland sleeve 34. I

The volume of liquid metal 9 inthe circulating system is sufiicient totill the wells 32 at all times and to maintain a certain depth of theliquid within the tanks 30. Each tank has suflicient capacity to containthe entire volume .of the circulating liquid. Electrodes 43 and 44extending downward within the tank 30 serve as a means to indicate thelevel of the liquid within the tank.

The circulation of the liquid metal or alloy throughout a closed circuitis maintained by a'pump 45. The closed circuit for the liquid extendsfrom the outlet side of the pump through a pipe line or conduit 46 whichincludes a heat exchanger 52 to and through a flexible connection orbellows 47 by which 'pipe 46 is attached to the lower end of the well 32beneath the tank 30 The circuit continues from said well upward throughthe inner tube 26 of the assembly 23 and through a lateral inlet channel49 (FIG. 6) in the arm 21 to the chamber 1 6. The circuit continues fromthe chamber 16 through an outlet channel 48 in the arm to the tube 26 ofthe assembly 22 and through said tube and associated well 32 and thencethrough a return pipe 50 to the pump 45.

The pipe line 46 extends through a heat exchanger 52 (FIG. 5) which maybe of conventional construction including a series of perforated metalplates. Cooling water is circulated through a pipe line 53 which extendsthrough the heat exchanger 52 for extracting heat fromthe liquid metal.A pipe line 54-extending through a second heat exchanger 54 provides abypass around the pump 45 through which the'liquid metal may becirculated when desired. A filter 55 in the bypass line serves forremoving oxides or impurities from the liquid metal. Hand valves 56 and57 in the pipe lines 46 and 54 respectively are operable to selectivelycontrol the flow through the main circulating system and the bypass.Dump valves 58 and 58 permit the liquid metal to be drawn from thecirculating system into a sump tank 60. The latter is sealed to preventaccess of air or moisture into the circulating system or into contactwith the liquid metal. The term liquid metal is intended to includemetal alloys except where otherwise indicated.

The construction comprised in the assembly 22 through which the liquidmetal is conducted to the cooling chamber 16 is a substantial duplicateof the assembly 23 as above described and as shown in section, FIG. 6.

Modifications may be resorted to Within the spirit and scope of ourinvention.

We claim:

1. In an apparatus for extracting heat from a vertically reciprocablemold element at high temperatures, said apparatus including meansdefining a cooling chamber in said mold element having an inlet and anoutlet, and means including a pump and a heat exchanger connectedbetween said inlet and said outlet and defining, with said coolingchamber, a closed heat exchange circuit through which a liquid metalheat exchanging fluid may be circulated; the improvement wherein saidlast named means further comprises a pair of stationary tanks eachadapted to contain a liquid metal heat exchanging fluid to apredetermined depth above the bottom thereof, an elongate well on eachtank in communication with the interior thereof and extending downwardlyfrom the bottom of the tank by a distance greater than the length of thevertical reciprocatory stroke of said mold element, a packing sleeveoneach tank extending upwardly from the top of. the tank, a'verticallyelongate outer tube received within each packing sleeve in slidablesealed engagement therewith, each. of said outer tubes being fixedlysecured at its upper end to said mold element for vertical reciprocationtherewith and having a length sufficient to maintain the outer tube inslidable sealed engagement with the associate packing sleeve throughoutfull range of vertical reciprocation of said mold element, an open endedinner tube coaxially mounted within each outer tube, means at the upperand lower ends of each outer tube sealing the associated inner tubethereto to define an annular chamber surrounding the innertube, eachinner tube projecting downwardly below the lower end of said outer tubeto a lower end located to be reciprocated within the associated wellduring reciprocation of said mold element, means connecting the upperend of one of'said inner tubes to said inlet of said chamber, meansconnecting the upper end of the other inner tube with said outlet ofsaid chamber, and conduit means connecting said pump and said heatexchanger in series between the respective lower ends of said wells.

2. In an apparatus as defined in claim 1, means in each of said packingsleeves defining spaced upper and lower sliding seals between the sleeveand associated upper tube, and means for maintaining an inert gas at apredetermined pressure within said tank above the surface of liquidmetal heat exchange iiuid contained therein and between said upper andlower seals.

References Cited in the file of this patent UNITED STATES PATENTS1,671,674- Fithiau May 29, 1928 1,922,509 Thurm Aug. 15, 1933 l,949, 899Collins et al. Mar. 6, 1934 2,402,708 Stewart et a1. June 25, 19462,508,890 Rowe May 23, 1950 2,508,891 Rowe May 23, 1950 2,693,347Rheaume Nov. 2, 1954 2,882,647 Tallent Apr. 21, 1959 2,901,865 McCormickSept. 1, 1959 FOREIGN PATENTS .3 Au l a y 50

1. IN AN APPARATUS FOR EXTRACTING HEAT FROM A VERTICALLY RECIPROCABLEMOLD ELEMENT AT HIGH TEMPERATURES, SAID APPARATUS INCLUDING MEANSDEFINING A COOLING CHAMBER IN SAID MOLD ELEMENT HAVING AN INLET AND ANOUTLET, AND MEANS INCLUDING A PUMP AND A HEAT EXCHANGER CONNECTEDBETWEEN SAID INLET AND SAID OUTLET AND DEFINING, WITH SAID COOLINGCHAMBER, A CLOSED HEAT EXCHANGE CIRCUIT THROUGH WHICH A LIQUID METALHEAT EXCHANGING FLUID MAY BE CIRCULATED, THE IMPROVEMENT WHEREIN SAIDLAST NAMED MEANS FURTHER COMPRISES A PAIR OF STATIONARY TANKS EACHADAPTED TO CONTAIN A LIQUID METAL HEAT EXCHANGING FLUID TO APREDETERMINED DEPTH ABOVE THE BOTTOM THEREOF, AN ELONGATE WELL ON EACHTANK IN COMMUNICATION WITH THE INTERIOR THEREOF AND EXTENDING DOWNWARDLYFROM THE BOTTOM OF THE TANK BY A DISTANCE GREATER THAN THE LENGTH OF THEVERTICAL RECIPROCATORY STROKE OF SAID MOLD ELEMENT, A PACKING SLEEVE ONEACH TANK EXTENDING UPWARDLY FROM THE TOP OF THE TANK, A VERTICALLYELONGATE OUTER TUBE RECEIVED WITHIN EACH PACKING SLEEVE IN SLIDABLESEALED ENGAGEMENT THEREWITH, EACH OF SAID OUTER TUBES BEING FIXEDLYSECURED AT ITS UPPER END TO SAID MOLD ELEMENT FOR VERTICAL RECIPROCATIONTHEREWITH AND HAVING A LENGTH SUFFICIENT TO MAINTAIN THE OUTER TUBE INSLIDABLE SEALED ENGAGEMENT WITH THE ASSOCIATE PACKING SLEEVE THROUGHOUTFULL RANGE OF VERTICAL RECIPROCATION OF SAID MOLD ELEMENT AN OPEN ENDEDINNER TUBE COAXIALLY MOUNTED WITHIN EACH OUTER TUBE, MEANS AT THE UPPERAND LOWER ENDS OF EACH OUTER TUBE SEALING THE ASSOCIATED INNER TUBETHERETO TO DEFINE AN ANNULAR CHAMBER SURROUNDING THE INNER TUBE, EACHINNER TUBE PROJECTING DOWNWARDLY BELOW THE LOWER END OF SAID OUTER TUBETO A LOWER END LOCATED TO BE RECIPROCATED WITHIN THE ASSOCIATED WELLDURING RECIPROCATION OF SAID MOLD ELEMENT, MEANS CONNECTING THE UPPEREND OF ONE OF SAID INNER TUBES TO SAID INLET OF SAID CHAMBER, MEANCONNECTING THE UPPER END OF THE OTHER INNER TUBE WITH SAID OUTLET OFSAID CHAMBER, AND CONDUIT MEANS CONNECTING SAID PUMP AND SAID HEATEXCHANGER IN SERIES BETWEEN THE RESPECTIVE LOWER ENDS OF SAID WELLS.